1. Field of the Invention
The present invention relates to an image forming process and apparatus therefor for forming an image with liquid ink in response to output information from a facsimile or a computer or optical information.
2. Description of the Prior Art
Image forming processes with liquid ink have been widely utilized particularly in the field of data processing for realizing noiseless, vibration-free printing devices. In a typical process ink drops are successively emitted toward a recording material, and the flight of said ink drops is controlled according to the information signals so as to deflect, during said flight, the unnecessary ink drops from the movement toward the recording material thereby forming an image corresponding to the information signals. In such process, however, ink drops flying across a very small distance have to be controlled during a very short period of flight, and the precision of image formation is inevitably limited as an exact control according to the information signals is difficult to achieve. Also there is required a circulation mechanism for recovering and reusing the thus deflected ink drops, which inevitably enlarges the dimension of the apparatus.
In an another image forming process plural ink supply holes or nozzles are provided in front of a recording material behind which independent pin electrodes are provided respectively corresponding to said nozzles and high-voltage pulses corresponding to the information signals are selectively applied between the nozzles and pin electrodes to cause flight of liquid ink thereby forming an image. This process provides an improved image precision as the information signals can be exactly applied to each nozzle. Also the apparatus can be made compact as the unnecessary ink drops are not created instead of being deflected during the flight, so that the circulation of ink drops is unnecessary. For improving the precision of image formation, however, it is necessary to maintain exact alignment between the nozzles and pin electrodes, and said alignment is very difficult to achieve in the structure of the apparatus as said nozzles and pin electrodes are both very small. Even a slight positional aberration between the two will result in a deterioration in the image precision. Also the pin electrodes receiving high-voltage pulses inevitably result in mutual interaction between the neighboring electrodes when they are arranged in a high density. For this reason it is impossible to obtain a high resolution in this process.